• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.543-551
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• 2021

Changes in gluten surface hydrophobicity, which play an important role in the functional characteristics of protein, were measured according to various protein concentrations, pH levels, electrolytes concentrations, and alginate molecular weights using 8-anilino-1-naphthalene sulfonic acid (ANS) as a fluorescent probe. Gluten surface hydrophobicity decreased as gluten concentration increased, reaching a maximum pH of 7.0. The effects of alginate molecular weights and alginate concentration on the surface hydrophobicity, emulsifying activity index (EAI), and emulsion stability index (ESI) of gluten-sodium alginate dispersion (GAD) were measured. Gluten surface hydrophobicity rapidly increased the asl NaCl concentration of gluten solution up to 300 mM and showed no significant increase above 300 mM. However, gluten surface hydrophobicity notably decreased until the concentration of CaCl₂ and MgCl₂ reached 30 mM, indicating no significant variations above 30 mM. GAD surface hydrophobicity increased as the concentration and molecular weight of sodium alginate increased, however, gluten concentration increased as the GAD surface hydrophobicity decreased. The EAI and ESI of GAD increased as both molecular weight and concentration of sodium alginate increased.

• Food Science of Animal Resources
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• v.31 no.5
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• pp.727-730
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• 2011

The effects of various NaCl levels (0, 0.3, and 0.6 M) and pH values (pH 5.0, 5.5, 6.0, and 6.5) on the emulsifying and gelling properties of pork myofibrillar protein (MP) were assessed. The emulsion stability index (ESI), emulsifying activity index (EAI), and creaming index were measured at a 1:20 ratio of MP to corn oil. The EAI and ESI of pork MP showed maximum values at pHs 6.0 and 6.5 and at 0.3 M NaCl, resulting in better emulsion properties. Additionally, the cooking yield (CY) and gel strength (GS) of emulsified MP gel were measured at an MP: corn oil ratio of 1: 2; GS increased with increasing levels of salt. At 0.6 M NaCl, GS decreased with decreasing pH from 5.5 to 6.5. GS and gelling properties were optimal at pH 5.5 in 0.6 M salt. The highest CY was observed at 0.6 M NaCl, regardless of the pH value. However, increasing pH increased CY at salt levels of 0 and 0.3 M. These results indicate that NaCl and pH profoundly affected the emulsified MP system. Future work will be conducted on the rheological properties of the pork emulsified system as affected by adding non-meat protein.

• Food Science of Animal Resources
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• v.35 no.3
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• pp.315-321
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• 2015

The aim of the present work was to investigate the effect of NaCl concentration on the emulsifying and rheological properties of porcine myofibrillar protein (MF)-stabilized soybean oil and fish oil emulsion (SO-EMs and FO-EMs). Emulsions (EMs) were prepared from 1% MF with 10% SO or FO at various NaCl concentration (0-0.5 M). The emulsifying ability index (EAI) of the EMs increased with increasing NaCl concentration for both oil types. Conversely, increasing NaCl manifested decrease in the emulsion stability index (ESI). In addition, creaming index (CI) also increased with NaCl concentration. From the microscopic observation, droplets of the EMs were more aggregated at relatively higher NaCl concentrations, especially for FO-EMs. All EMs had a gel-like structure owing to G' > G" from the rheological analysis. Comparing the oil types, the emulsifying capacity of SO-EMs was more stable than that of FO-EMs at all NaCl concentrations as determined from the CI value and microscopic observation. Therefore, it can be concluded that SO-EMs and FO-EMs are more stable at relatively lower concentrations of NaCl. In addition, the dispersed stability of SO-EMs was better than that of FO-EMs at the same concentration of NaCl.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.4
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• pp.320-326
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• 2001

To obtain the basic data for preparing edible or biodegradable film, fish meal protein isolates (FMPI) were prepared through alkaline extraction. And FMPI's properties and the ester compounds permeability of FMPI film were measured. FMPI were extracted under various extracting time with 0.2 N NaOH solution at $60^{\circ}C$, Recovery ratios of FMPI extracted from fish meal were increased with extracting time increasing. Surface hydrophobicity of FMPI extracted for 1 hr showed highest value. Emulsifying activity index (EAI) was increased with the increasement of extracting time but its emulsifying stability index (ESI) showed an inverse results. Viscosity of FMPI solution showed the highest value at pH 2 but showed the lowest value at pH 4, The higher concentration of sorbitol as plasticizer showed the higher ethyl acetate permeability of FMPI film, Ethyl acetate permeability of FMPI films according to kind of plasticizers showed different degree and increased in order as follow: polyethylene glycol, glycerol and sorbitol. Ester compounds having the lower molecular weight showed the higher permeability. Increment of temperature increased the ethyl acetate permeability of FMPI film. FMPI haying higher surface hydrophobicity made FMPI film be higher tensile strength. On elongation of FMPI films, kinds of plasticizer were more effective than surface hydrophobicity of FMPI.

• Food Science of Animal Resources
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• v.34 no.6
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• pp.808-814
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• 2014

This study investigated the effect of gum arabic (GA) combined with microbial transglutaminase (TG) on the functional properties of porcine myofibrillar protein (MP). As an indicator of functional property, heat-set gel and emulsion characteristics of MP treated with GA and/or TG were explored under varying NaCl concentrations (0.1-0.6 M). The GA improved thermal gelling ability of MP during thermal processing and after cooling, and concomitantly added TG assisted the formation of viscoelastic MP gel formation. Meanwhile, the addition of GA decreased cooking yield of MP gel at 0.6 M NaCl concentration, and the yield was further decreased by TG addition, mainly attributed by enhancement of protein-protein interactions. Emulsion characteristics indicated that GA had emulsifying ability and the addition of GA increased the emulsification activity index (EAI) of MP-stabilized emulsion. However, GA showed a negative effect on emulsion stability, particularly great drop in the emulsion stability index (ESI) was found in GA treatment at 0.6 M NaCl. Consequently, the results indicated that GA had a potential advantage to form a viscoelastic MP gel. For the practical aspect, the application of GA in meat processing had to be limited to the purposes of texture enhancer such as restructured products, but not low-salt products and emulsion-type meat products.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1093-1101
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• 2000

The effects of concentration and pH on the emulsifying and rheological properties of the pine nut's protein extract(PNPE) and carbohydrate extract(PNCE) were investigated. Emulsifying activity index(EAI) of sample containing PNPE was minimal at pH 4.0 and the alteration of pH from 4 to 3 or 8 increased EAI regardless of concentration. The most EAI(about 6.44 $m^2/g$ solid) significantly(p<0.05) observed in solution containing 1% PNPE at pH 8.0, but that of 3% PNPE(0.10 $m^2/g$ solid) was minimal at pH 4.0. The emulsion stability exhibited maximum value(about 20) in 3% PNPE emulsion at pH 8.0. However, EAI of samples containing PNCE increased gradually with the increase of pH, but it had lower value than that of samples containing PNPE. At pH 7.0 and 8.0, the rheological behavior of emulsion solutions showed Newtonian fluid(n=1, $r^2>0.99$) regardless of concentration in all samples containing PNPE, but the samples containing PNCE showed pseudoplastic behavior(n<1) in all conditions. The sample with the better emulsion stability index(ESI) significantly(p<0.05) exhibited the higher L, b, and ${\delta}E$, however, lower a value.